First Australian report of vitamin D-dependent rickets type I

A 20-month-old girl presented to hospital with features of rickets. Results of investigations were consistent with vitamin D-dependent rickets type I (VDDR-I), and DNA sequence analysis showed a homozygous mutation in the CYP27B1 gene of c.1325-1326insCCCACCC. This is the first reported Australian case of VDDR-I.

Clinical record

A 20-month-old white Australian girl presented to the Women’s and Children’s Hospital in Adelaide, South Australia, with a 6-month history of developmental regression of gross motor skills, failure to thrive and irritability, in particular distress when “she was wearing her shoes”. At 14 months of age, she had been crawling, pulling to stand and cruising, but at presentation her gross motor skills had regressed to only being able to sit unsupported. Other developmental milestones continued to progress normally for her age. Her weight at presentation was 7.7 kg, having dropped from the 50th centile to below the third centile (weight loss of 3.7 kg over 6 months). Length and head circumference had dropped from the 25th centile to less than the first centile and to the third centile, respectively, over this time.

The patient was the second child born to non-consanguineous white Australian parents. She was born at term with no perinatal complications. There was no history of familial hereditary disease. Maternal vitamin D deficiency had been treated during the pregnancy.…